The present invention relates to monitoring devices or modules packaged within a container. In one aspect, the present invention is particularly useful in inventory control.
Various systems allow a user to track devices or packages. For example, a barcode containing a model number or a serial number or other identifying indicia can be printed on a device or a package An optical scanner connected to a tracking system can scan the barcode, so that the tracking system can determine the identity and location of the marked item. Such barcode systems rely on a “line of sight” access from the barcode reader to the barcode on the item being tracked. In addition, while the tracking system can record various information pertaining to the location and status of the tracked item, the item tracked does not itself retain any information as to where it has been, or what processing steps have been performed on it.
More recently, radio frequency transmitters have been applied to devices for tracking purposes. Such radio frequency transmitters contain information that they can transmit to a reader. The radio frequency transmitters do not require a “line of sight” access from the reader.
Magnetic tags and sensors have also been demonstrated to track and verify the identity of products. Magnetic tags require close proximity between the information bearing tag and the sensor.